We pose an experimental model for hot deformation that, in complexity, fall
s between a homogeneous laboratory test and an industrial process. Our obje
ctive is to document a transition between two distinct models of thermally-
activated deformation: diffusion controlled solute drag and hardening with
concurrent recovery of dislocations. We demonstrate that constitutive equat
ions for plasticity, describing different regimes of dislocation kinetics a
nd calibrated with a minimum of adjustable constants, can be incorporated i
nto finite element analysis and used reliably to predict the mechanical res
ponse to a nonuniform body. [S0094-4289(00)00302-9].